Small Engines (Lawn Mowers, etc.): Kohler engine K321qs knocks, head gasket, power tune

Question
Hi.
I have a jacobsen with the mentioned engine, when it´s going without load, then it´s going perfect but when the load is on, then after a while, the engine starts "knocking" and it loose power. Can it be wrong setting of the breaker points ?

Answer
Could be, .020. but I doubt it.  More likely a coil or condenser.  The points are at the same setting when it runs good as when it runs bad and they are not a load/heat sensitive item.

If this unit came into my shop with this problem I would do a major engine service.  That would include, points, condenser, cleaning the carb, and replaceing the head gasket.   Kohler calls this a power tune.  The results are amazing.  

Dificulty level: 3, on a 1 - 10 scale.